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ToxFAQsTM for Naphthalene, 1-Methylnapthalene,
2-Methylnapthalene

This fact sheet answers the most frequently
asked health questions about naphthalene, 1-methylnapthalene,
and 2-methylnapthalene. For more information, you may call
the ATSDR Information Center at 1-800-232-4636. This fact
sheet is one in a series of summaries about hazardous substances
and their health effects. This information is important because
this substance may harm you. The effects of exposure to any
hazardous substance depend on the dose, the duration, how
you are exposed, personal traits and habits, and whether other
chemicals are present.

Highlights

Exposure to naphthalene,
1-methylnaphthalene, or 2-methylnaphthalene happens mostly
from breathing air contaminated from the burning of wood,
tobacco, or fossil fuels, industrial discharges, or moth
repellents. Exposure to large amounts of naphthalene may
damage or destroy some of your red blood cells. Naphthalene
has caused cancer in animals. Naphthalene, 1-methylnaphthalene,
and 2-methylnaphthalene have been found in at least 687,
36, and 412, respectively, of the 1,662 National Priority
List sites identified by the Environmental Protection
Agency (EPA).

What are naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene?

Naphthalene is a white solid that evaporates
easily. Fuels such as petroleum and coal contain naphthalene.
It is also called white tar, and tar camphor, and has been
used in mothballs and moth flakes. Burning tobacco or wood
produces naphthalene. It has a strong, but not unpleasant
smell. The major commercial use of naphthalene is in the manufacture
of polyvinyl chloride (PVC) plastics. Its major consumer use
is in moth repellents and toilet deodorant blocks.

1-Methylnaphthalene and 2-methylnaphthalene
are naphthalene-related compounds. 1-Methylnaphthalene is
a clear liquid and 2-methylnaphthalene is a solid; both can
be smelled in air and in water at very low concentrations. 1-Methylnaphthalene and 2-methylnaphthalene are used to make
other chemicals such as dyes and resins. 2-Methylnaphthalene
is also used to make vitamin K.

How can naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene affect my health?

Exposure to large amounts of naphthalene
may damage or destroy some of your red blood cells. This could
cause you to have too few red blood cells until your body
replaces the destroyed cells. This condition is called hemolytic
anemia. Some symptoms of hemolytic anemia are fatigue, lack
of appetite, restlessness, and pale skin. Exposure to large
amounts of naphthalene may also cause nausea, vomiting, diarrhea,
blood in the urine, and a yellow color to the skin. Animals
sometimes develop cloudiness in their eyes after swallowing
high amounts of naphthalene. It is not clear whether this
also develops in people. Rats and mice that breathed naphthalene
vapors daily for a lifetime developed irritation and inflammation
of their nose and lungs. It is unclear if naphthalene causes
reproductive effects in animals; most evidence says it does
not.

There are no studies of humans exposed
to 1-methylnaphthalene or 2-methylnaphthalene.

Mice fed food containing 1-methylnaphthalene
and 2-methylnaphthalene for most of their lives had part of
their lungs filled with an abnormal material.

How likely are naphthalene, 1 methylnaphthalene, or 2 methylnaphthalene to cause cancer?

There is no direct evidence in humans
that naphthalene, 1-methylnaphthalene, or 2-methylnaphthalene
cause cancer. However, cancer from naphthalene exposure has
been seen in animal studies. Some female mice that breathed
naphthalene vapors daily for a lifetime developed lung tumors.
Some male and female rats exposed to naphthalene in a similar
manner also developed nose tumors.

Based on the results from animal studies, the Department of
Health and Humans Services (DHHS) concluded that naphthalene
is reasonably anticipated to be a human carcinogen. The International
Agency for Research on Cancer (IARC) concluded that naphthalene
is possibly carcinogenic to humans. The EPA determined that
naphthalene is a possible human carcinogen (Group C) and that
the data are inadequate to assess the human carcinogenic potential
of 2-methylnaphthalene.

How can naphthalene, 1-methylnaphthalene, or 2-methylnaphthalene affect children?

Hospitals have reported many cases of
hemolytic anemia in children, including newborns and infants,
who either ate naphthalene mothballs or deodorants cakes or
who were in close contact with clothing or blankets stored
in naphthalene mothballs. Naphthalene can move from a pregnant
woman's blood to the unborn baby's blood. Naphthalene has
been detected in some samples of breast milk from the general
U.S. population, but not at levels that are expected to be
of concern.

There is no information on whether naphthalene
has affected development in humans. No developmental abnormalities
were observed in the offspring from rats, mice, and rabbits
fed naphthalene during pregnancy.

We do not have any information on possible
health effects of 1-methylnaphthalene or 2-methylnaphthalene
on children.

How can families reduce the risks of exposure to naphthalene, 1 methylnaphthalene, and 2 methylnaphthalene?

Families can reduce the risks of exposure to naphthalene,
1-methylnaphthalene, and 2-methylnaphthalene by avoiding
smoking tobacco, generating smoke during cooking, or using
fireplaces or heating appliances in the their homes.

If families use naphthalene-containing moth repellents,
the material should be enclosed in containers that prevent
vapors from escaping, and kept out of the reach from children.

Blankets and clothing stored with naphthalene moth repellents
should be aired outdoors to remove naphthalene odors and
washed before they are used.

Families should inform themselves of the contents of air
deodorizers that are used in their homes and refrain from
using deodorizers with naphthalene.

Is there a medical test to determine whether I've been exposed to naphthalene, 1 methylnaphthalene, and 2 methylnaphthalene?

Tests are available that measure levels
of these chemicals and their breakdown products in samples
of urine, feces, blood, maternal milk, or body fat. These
tests are not routinely available in a doctor's office because
they require special equipment, but samples can be sent to
special testing laboratories. These tests cannot determine
exactly how much naphthalene, 1-methylnaphthalene, or 2-methylnaphthalene
you were exposed to or predict whether harmful effects will
occur. If the samples are collected within a day or two of
exposure, then the tests can show if you were exposed to a
large or small amount of naphthalene, 1-methylnaphthalene,
or 2-methylnaphthalene.

Has the federal government made recommendations to protect human health?

The EPA recommends that children not
drink water with over 0.5 parts per million (0.5 ppm) naphthalene
for more than 10 days or over 0.4 ppm for any longer than
7 years. Adults should not drink water with more than 1 ppm
for more than 7 years. For water consumed over a lifetime
(70 years), the EPA suggests that it contain no more than
0.1 ppm naphthalene.

The Occupational Safety and Health Administration (OSHA) set a limit of 10 ppm for the level of naphthalene in workplace air during an 8-hour workday, 40-hour workweek. The National Institute for Occupational Safety and Health (NIOSH) considers more than 500 ppm of naphthalene in air to be immediately dangerous to life or health. This is the exposure level of a chemical that is likely to impair a worker's ability to leave a contaminate area and therefore, results in permanent health problems or death.

ATSDR can also tell you the location of occupational and environmental health clinics. These clinics specialize in
recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances.

Information line and technical assistance:
Phone: 888-422-8737

To order toxicological profiles, contact:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Phone: 800-553-6847 or 703-605-6000

Disclaimer
Some PDF files may be electronic conversions from paper copy or other electronic ASCII text files. This conversion may have resulted in character translation or format errors. Users are referred to the original paper copy of the toxicological profile for the official text, figures, and tables. Original paper copies can be obtained via the directions on the toxicological profile home page, which also contains other important information about the profiles.

The information contained here was correct at the time of publication. Please check with the appropriate agency for any changes to the regulations or guidelines cited.